It has been practice to construct contour-cutting machines, with a vertical cutting element in the cutting region, which is guided through a gap in the workpiece table (European patent 0 738 569 A1, inventor: Hueskens). The cutting assembly comprises an open gantry in which there are installed four deflecting pulleys for the cutting element, and the gantry can be displaced in its entirety in order to guide the cutting element along the table gap. In a first embodiment, the main plane of the cutting gantry coincides with the table-gap plane, and such gantry has double the width of the workpiece table making the all-over dimension of the machine very extensive. In the second embodiment, the main plane of the gantry extends perpendicularly to the table gap, and the full width of the contour-cutting machine does only exceed the width of the workpiece table to a small extent, but the gantry has to be designed with high level of rigidity, this resulting in large masses having to be moved.
In order to avoid large masses having to be moved, it is already known from my previous invention (European patent 0 390 939 A1) to provide a stationary cutting-assembly carrier with a top and bottom tool carriage or slide, between which the cutting element is tensioned and which are displaced parallel to the table gap. In the case of a continuous band knife as the cutting element, a storage loop is formed, the latter supplying the missing band-knife length and/or taking up the excess band-knife length. The loop formation of the band knife is not desirable and can be avoided by a contour-cutting machine designed according to a further invention of mine (German publication 195 49 458 A1). However, the stationary frame, which encloses the workpiece table in the vicinity of the table gap, is of double the table width. Four pulleys are used in order to tension and to guide the cutting element in rectangular form. Each of the pulleys in this case is seated on its own carriage or slide and is displaced synchronously on guides parallel to the table gap. Smaller masses are moved as a result. However, the large width of the stationary frame is not desirable.